The antimicrobial agents chlorhexidine ("CHX"; 1,6 bis(N.sup.5 -p-chlorophenyl-N.sup.1 -biguanido)hexane), benzalkonium chloride ("BZK") and parachlorometaxylenol ("PCMX") have been used, individually, in antimicrobial compositions. For example, the well-known antiseptic scrubs Hibiclens.RTM., Ultradex.RTM. and Techni-care contain 4% CHX (Hibiclens.RTM.) and 3% PCMX (Ultradex.RTM. and Technicar.RTM.). The use of these scrubs, however, provides less than optimal antimicrobial protection, in that neither scrub is believed to be fully effective in rapidly inactivating pathogens or in reducing skin flora for an extended period of time. Furthermore, the relatively high levels of antimicrobial agents in these preparations are frequently associated with skin irritation.
Compositions which combine one or more of the foregoing antimicrobial agents with additional compounds are also known, as illustrated by the following references.
U.S. Pat. No. 5,244,666 by Murley, issued Sep. 14, 1993 ("the '666 patent") relates to an antiseptic scrub and wound disinfectant wherein a quaternary ammonium compound and a substituted phenolic compound are combined to produce enhanced antimicrobial activity at lower concentrations. The '666 patent states that the use of such combinations, together with degreasing emulsifiers, detergents, skin softeners and soothing agents is new. The compositions comprise about 3% (wt/wt) of a quaternary ammonium compound and about 3% of a substituted phenolic compound.
U.S. Pat. No. 5,030,659 by Bansemir et al., issued Jul. 9, 1991 ("the '659 patent") relates to disinfectant compositions comprising a quaternary ammonium compound, a biguanide, and a phenolic compound. The antimicrobial agent present in greatest concentration is the quaternary ammonium compound; the working examples of the '659 patent include compositions comprising 15-20% of the quaternary ammonium compound BZK.
U.S. Pat. No. 4,900,721 by Bansemir et al., issued Feb. 13, 1990, relates to liquid, aqueous disinfectants based on alcohol and hydrogen peroxide which comprise one or more C.sub.2 -C.sub.8 alcohols, hydrogen peroxide (or a compound which produces hydrogen peroxide), one or more carboxylic acids, one or more microbicidally active nitrogen-containing organic compounds (e.g., CHX or BZK), and one or more microbicidally active phenolic compounds (including polychlorinated xylenes).
U.S. Pat. No. 4,420,484 by Gorman et al., issued Dec. 13, 1983, relates to combinations of antimicrobial agents (such as CHX or BZK) with polyethylene glycol surfactant and betaine or amine oxide surfactant.
U.S. Pat. Nos. 4,125,628 and 4,022,911, by Goldhaft et al., issued Nov. 14, 1978 and May 10, 1977, respectively, relate to combinations of a quaternary ammonium compound, a phenol or derivative thereof, and formaldehyde.
U.S. Pat. No. 3,639,632 by McNamara et al., issued Feb. 1, 1972, relates to a synergistic antimicrobial composition containing 1,1'-hexamethylenebis [5-(2-ethylhexyl)biguanide] dihydrochloride and 4-chloro-2-hydroxyphenyl, 2,4-dichlorophenyl ether.
Larson et al., 1992, J. Emergency Med. 10: 7-11 discloses that in the presence of blood, topical antimicrobial products containing alcohol were associated with greater initial reductions in colonizing flora.
The number of antimicrobial preparations which have been developed illustrates the continuing search for a composition that rapidly and effectively provides antimicrobial activity without substantial adverse effects, such as skin irritation.